Automatic document processing apparatus

ABSTRACT

A ported belt type single sheet feeder having a variable speed drive transmission between means for driving the belt and a rotary valve controlling application of subatmospheric pressure to a shoe behind the ported belt to permit variation of the frequency of application of the subatmospheric pressure in the shoe relative to the speed of the drive of the belt so as to vary the spacing of sheets drawn onto the belt.

United States Patent [72] lnventor Leslie John Street Cotham Park, Bristol, England [21 Appl. No. 746,345

[22] Filed July 22, 1968 [45] Patented Feb. 16, 1971 [73] Assignee Parnall & Sons Limited Birmingham, England a British Company [32] Priority Aug. 18, 1967 [33] Great Britain [54] AUTOMATIC DOCUMENT PROCESSING APPARATUS 3 Claims, 3 Drawing Figs.

[52] US. Cl. 271/26; 271/34 [51] Int. Cl B65h 3/12 [50] Field ol'Search 271/26- [56] References Cited UNITED STATES PATENTS 3,212,772 10/1965 Ward 271/32 Primary Examiner-Even C. Blunk Assistant ExaminerW. Scott Carson Attorney-Norris & Bateman ABSTRACT: A ported belt type single sheet feeder having a variable speed drive transmission between means for driving the belt and a rotary valve controlling application of subatmospheric pressure to a shoe behind the ported belt to permit variation of the frequency of application of the subatmospheric pressure in the shoe relative to the speed of the drive of the belt so as to vary the spacing of sheets drawn onto the belt.

AUTOMATIC DOCUMENT PROCESSING APPARATUS belt to that of the top document with means for establishing subatmospheric pressure in the shoe for drawing through the ports a succession of documents on to the belt and thereby transporting the documents on the belt in spaced sequence away from the stack.

ln previously known feeders of the aforesaid kind the spacing between the sequence of single documents has been determined by the fixed spacing .of the ports along the length of the belt, and the present invention has for its object to permit ready variation of the spacing between the sequence of documents.

The invention consists of a single document feeder of the kind hereinbefore defined characterized by the provision of a variable speed drive transmission between means for driving the belt and means for intermittently establishing subatmospheric pressure in the shoe whereby the frequency of the establishment of partial vacuum in the shoe can be varied in relation to the speed of the belt drive.

One example of the practical realization of the invention is described with reference to the accompanying drawings wherein: I

FIGS. 1, 2 and 3 show apparatus according to the invention in side elevation, end elevation and plan view respectively.

Referring to the drawings, a document processing apparatus comprises a single document feeder including a holder 4 for receiving a stack of documents 5, and a pair of endless belts 6 running about and between a pair of pulley wheels 7a, 7b with a part of one run of the belts overlying the top document of the stack. The belts are each provided with equally spaced apart ports 8 along its entire length and a vacuum shoe 9 is fixed to overlie the opposite faces of thebelts to those in proximity with the top document. The shoe 9 has connection with a vacuum pump (not shown) so that subatmospheric pressure established in the shoe acts through the belt ports 8 as they are presented before the shoe to suck the top document on to the adjacent faces of the belts whereby the document is transported along the belts for delivery to secondary transporting means (not shown).

One of the belt supporting pulley wheels 7a is continuously driven by an electric motor 10 via shaft 11 and this same drive also has connection via drive belt 12 with the input 13 to a variable speed gear box 14. The output 15 of this variable speed gear box 14 has connection with a rotary valve 16 in the vacuum line 17, 18 to the shoe whereby the subatmospheric pressure is intermittently established in the shoe 9 at intervals synchronized with the drive of the belts 6. By variation of the ratio between the input and output of the variable speed gear box 14 the frequency of establishment of subatmospheric pressure in the shoe 9 can be varied in relation to the speed of the belts 6 and hence the spacing between the documents abstracted by the belt and shoe can be readily varied.

It is conventional practice to provide means, for example counter moving belts or vacuum shoes, acting on the opposite sides of a document on the ported belts to the belts whereby any second document adhering to the first document is temporarily arrested. it is envisaged that the present invention can alsobe employed to control the drive or energization of this second sheet rejector means from the output of the variable speed gear box.

lclaim:

l. A document feeder for extracting single documents in succession from a stack comprising at least one ported and endless belt, means for driving the belt, a fixed shoe disposed on one side of a run of said belt, and a vacuum line connected to the shoe for establishing subatmospheric pressure in the shoe servin to draw through the ports a document from the stack onto t e belt, characterized y means for interm ttently establishing subatmospheric pressure in the shoe comprising rotary valve means in said vacuum line, and variable speed drive transmission means between the means for driving the belt and said valve means comprising a variable speed gear frequency of the establishment of subatmospheric pressure in the shoe can be varied in relation to the speed of drive of the belt to selectively vary the spacing between the sequence of sheets extracted from the stack.

2. A document feeder for extracting single documents in succession from a stack comprising a ported belt having a run disposed in feeding relation to an exposed document of the stack, means for driving said belt at a selected speed, means for intermittently producing a vacuum pull through said run of the belt to periodically draw said exposed document onto the belt and extract it from said stack, and means for establishing a predetermined spacing between successive documents on said belt comprising means for selectively varying the frequency of said vacuum pull.

3. The document feeder defined in claim 2 wherein said vacuum pull producing means comprises an apertured shoe over which passes said ported belt and to'which is connected a vacuum line having periodically actuated valve means, and said document spacing establishing means comprises a variable speed drive connection for said valve means. 

1. A document feeder for extracting single documents in succession from a stack comprising at least one ported and endless belt, means for driving the belt, a fixed shoe disposed on one side of a run of said belt, and a vacuum line connected to the shoe for establishing subatmospheric pressure in the shoe serving to draw through the ports a document from the stack onto the belt, characterized by means for intermittently establishing subatmospheric pressure in the shoe comprising rotary valve means in said vacuum line, and variable speed drive transmission means between the means for driving the belt and said valve means comprising a variable speed gear box having an input shaft connected to the belt drive and an output shaft connected to said valve means for intermittently establishing subatmospheric pressure in the shoe, whereby the frequency of the establishment of subatmospheric pressure in the shoe can be varied in relation to the speed of drive of the belt to selectively vary the spacing between the sequence of sheets extracted from the stack.
 2. A document feeder for extracting single documents in succession from a stack comprising a ported belt having a run disposed in feeding relation to an exposed document of the stack, means for driving said belt at a selected speed, means for intermittently producing a vacuum pull through said run of the belt to periodically draw said exposed document onto the belt and extract it from said stack, and means for establishing a predetermined spacing between successive documents on said belt comprising means for selectively varying the frequency of said vacuum pull.
 3. The document feeder defined in claim 2 wherein said vacuum pull producing means comprises an apertured shoe over which passes said ported belt and to which is connected a vacuum line having periodically actuated valve means, and said document spacing establishing means comprises a variable speed drive connection for said valve means. 